searxng: new chart (1.0.0+up2026.8.22.9fea41204)

SearXNG as a stateless Deployment plus a settings ConfigMap, with the four CI
steps a new chart needs: publish workflow, change-app-version choice list,
ci/searxng/ fixtures and a renovate.json5 block.

Three points where the chart is not a cyberchef with another name:

* The image entrypoint writes settings.yml into /etc/searxng only when the
  file is missing. The chart always mounts one by subPath, so the copy and
  the random-secret sed never run and the container needs no write access
  there - which is what allows readOnlyRootFilesystem: true.
* The signing key is a required OnePasswordItem, not a ConfigMap key. It
  signs the settings cookie and the image-proxy URLs, and the entrypoint's
  self-generating fallback cannot fire here, so without it the instance would
  run on the literal "ultrasecretkey" - which webapp.py refuses with exit 1.
* All three probes use /healthz, the only path the bot detection lets through
  unconditionally. Measured: with the limiter active, "/" answers 429 while
  /healthz still answers 200.

ingress.domain is read a second time outside the Ingress template, for
SEARXNG_BASE_URL, and carries its own required() there - so it stays
mandatory with the Ingress switched off.

The Renovate versioning regex deviates from the plan on the issue and matches
the commit hash WITHOUT capturing it. Renovate parses a "build" group with
Number.parseInt, so a hash becomes the digits leading it; measured on
renovate 41.173.1 and 44.48.0, the planned form reports an image pushed
earlier the same day as an update to a newer one. Reasoning in the block and
in README.

.github/workflows/change-app-version.yml

@@ -35,6 +35,7 @@ on:
           - minecraft-router
           - minecraft-server
           - rss-bridge
+          - searxng
           # freesailarr is deliberately absent: none of its nine images takes
           # its tag from appVersion (they are all pinned in its values.yaml),
           # so this workflow would rewrite appVersion and republish the chart